Abstract: The optimal process of extracting flavone from Pueraria by ethanol was studied and the optimal conditions were obtained by orthogonal matrix on the basis of single factor test in this paper. Meanwhile, the anti-oxidant activities of the extraction liquid were also studied by Pyrogallol-carbonate buffer-Luminol chemiluminescence system and Luminol-H2O2 chemilumines- cence system. The results showed that the optimal conditions by orthogonal matrix were in the following: time 1 hour, the temperature 80 ℃ the volume of ethanol 70% and the ratio of material to solvent 1:30. It was also found that the CL intensity of the Luminol - H2O2 system and Pyrogallol-carbonate buffer-Luminol system could be inhibited in the presence of flavonoids of pueraria. It was demonstrated that the flavonoe of Pueraria had powerful ability to clear off superoxide radicals (IC50=28.94 μg/ml) and hydrogen peroxide (IC50=6.30μg/ml).

Key words: Pueraria, flavone, extracting process, chemiluminescence, anti-oxidant activity